Self-Venting Adhesive Patch for Microwavable Food Packaging Bags

ABSTRACT

A self-venting adhesive patch and method of manufacture for frozen food product packages is provided. The patch is made from a film material having a permanent adhesive zone applied to a surface of the film material. A releasable adhesive zone adjacent to the permanent adhesive zone is defined on the surface of the film material and is also provided to allow for venting while cooking. A non-adhesive zone within the permanent adhesive zone on the surface of the film covers a vent formed in a microwavable packaging material covered by the self-venting adhesive patch. The non-adhesive zone directs steam pressure towards the releasable adhesive zone. A package formed from the microwavable packaging material vents steam to the self-venting adhesive generated during cooking of contents of the package. The steam expands the non-adhesive zone and vents into the releasable adhesive zone, allowing steam to be vented from the self-venting patch.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a non-provisional application claiming priority to U.S. Provisional Application No. 63/145,572 filed Feb. 4, 2021 hereby incorporated by reference for all purposes.

TECHNICAL FIELD

The present disclosure relates to food packaging bags and in particular to steam venting microwavable flexible packaging bags.

BACKGROUND

Flexible packaging bags built with laminated film structures can be used in microwave ovens to cook or reheat various types of foods. For some food products that are raw or pre-cooked the technology required for venting the packaging bags is more complex than simple open holes in the bag wall. Some food products require a closed system that has a hermetic seal until the time the product is cooked or reheated in the microwave. Some global markets require hermetically sealed packaging regardless of the products.

Common microwave steam venting methods use small slits or perforations in the packages but they are open to the elements at all times and not considered hermetically sealed. One of the solutions is to pack food in an airtight hermetically sealed package and have the end user puncture the bag with a sharp utensil creating a crude steam vent and then heating in the microwave. However the variability of steam vent rate can impact the consistency in the cooking of the food product. Alternatively the bag may be pre-perforated during manufacturing and then cover the opening with a releasable pressure sensitive adhesive patch. The end user is then tasked with manipulating or removing the patch before microwaving in order to open the steam vent holes.

Existing solutions require the end user to ensure venting occurs which adds variability to the outcome of the microwave cooking process and once the patch is removed the package is prone to leaking liquids and sauces when handling after cooking. If the vent has not been opened manually the bags may explode under pressure in the microwave. Other self-venting technologies rely on high temperatures to dissolve or melt bonds, seals and fillers, where fillers refer to a porous material filled with something that melts and that is what opens the vent. These solutions do not allow the package to be resealed and require a specific temperature to be achieved in order to dissolve or melt the bond.

Accordingly, systems and methods that enable improved venting of microwavable food packaging bags remains highly desirable.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the present disclosure will become apparent from the following detailed description, taken in combination with the appended drawings, in which:

FIG. 1 shows a representation of microwavable packaging bag having a self-venting adhesive patch;

FIG. 2 shows a top view of the self-venting adhesive patch;

FIG. 3 shows a side view of the self-venting adhesive patch while venting;

FIG. 4 shows a representation of a pillow packaging bag having a self-venting adhesive patch;

FIG. 5 shows a representation of a bottom gusset stand-up pouch bag having a self-venting adhesive patch;

FIG. 6 shows a representation of roll-stock having self-venting adhesive patches applied thereon;

FIG. 7 shows a method of manufacturing a flexible packaging bag having a self-venting adhesive patch; and

FIG. 8 shows a top view of an alternative venting adhesive patch.

It will be noted that throughout the appended drawings, like features are identified by like reference numerals.

DETAILED DESCRIPTION

Embodiments are described below, by way of example only, with reference to FIGS. 1-8.

One general aspect includes a self-venting adhesive patch made from a film material. The self—venting adhesive patch also includes a permanent stronger bond adhesive zone applied to a surface of the film material; a releasable lesser bond adhesive zone adjacent to the permanent adhesive zone on the surface of the film material; and a non-adhesive zone within the permanent adhesive zone on the surface of the film for covering a vent formed in a microwavable packaging material covered by the self-venting adhesive patch, the non-adhesive zone directing steam pressure towards the releasable adhesive zone; where a package, formed from the microwavable packaging material, vents steam pressure to the self-venting adhesive generated during cooking of contents of the package, the steam pressure expands the non-adhesive zone and vents into the releasable adhesive zone, allowing steam to be vented from the vent, through the releasable lesser bond adhesive zone.

Implementations may include one or more of the following features. The self-venting adhesive patch where the permanent adhesive is a stronger bond adhesive and the releasable adhesive zone is a lesser bond adhesive. The self-venting adhesive patch may include a separation zone between the permanent adhesive zone and the releasable adhesive zone. At least a portion of the separation zone may be formed by the permanent stronger bond adhesive zone. The non-adhesive zone is formed by application of a second film material over a portion of the permanent adhesive zone. The adhesives are food grade adhesives or adhesives suitable for indirect food contact. The vent within the packaging material the perforations are selected from a group may include: slits, round holes, semicircular cuts, cross shaped cuts, v-shaped cuts, needle punches, and laser perforations. The adhesive patch is applied to packaging material roll-stock prior to forming a package from the flexible packaging material. The adhesive patch is applied to a formed package aligned with a perforation in a wall of the formed package. The releasable adhesive can partially re-seal to the microwavable packaging material when cooled after being heated. The shape of the non-adhesive zone provides proportionally larger perimeter length with the permanent adhesive zone than a perimeter length of the releasable adhesive zone. The vent is formed by a semi-circular cut. The patch is circular in shape. The shape of the non-adhesive zone is triangular shaped. The shape of the non-adhesive zone is bulb shaped. A separation zone is between the permanent adhesive zone and the releasable adhesive zone. The releasable lesser bond adhesive zone is formed by a plurality of sub-zones. A method of manufacturing a flexible package with an adhesive patch, the method may include: receiving a rollstock material; perforating the rollstock material to form a vent opening; applying a self-venting adhesive patch to a side of the rollstock over the perforation in the rollstock material.

One general aspect includes a method of manufacturing an adhesive patch for application to a microwaveable package. The method of manufacturing also includes applying a permanent adhesive to a film material in a permanent adhesive zone; applying a releasable adhesive to the film material adjacent to the permanent adhesive in a releasable adhesive zone, where a non-adhesive zone is formed within the permanent adhesive zone which allows the releasable adhesive zone to release from microwavable package when steam pressure is released from moisture in food contents within the microwavable package.

Implementations may include one or more of the following features. The method where the adhesive patch is applied to roll-stock material for forming the flexible packaging material.

A self-venting adhesive patch is disclosed for “microwave in bag” applications. The self-venting adhesive patch covers a steam vent opening in microwavable food packaging bag and lifts away from the opening during cooking. The patch provides a self-venting solution for a hermetically sealed bag without requiring end user involvement in removing the patch or opening the vent prior to cooking. A portion of the patch remains anchored to the package at all times. The patch can be pre-applied to film, applied to a premade package during bag making or integrated inline at the packer and applied to the film web during packing. The patches can be applied in any location on the film web covering a vent opening in the film.

FIG. 1 shows a representation of microwavable packaging bag having a self-venting adhesive patch 100. The patch 100 can be made from film material with at least two different adhesive zones which adhere to a side 104 of a packaging bag 102. The package made from a laminated structure is sealed along the edges of the package 106. The food product can be placed within the bag through an opening 108 which is then sealed. The patch 100 can be clear, colored, opaque or printed with color ink or text.

FIG. 2 shows a top view of the self-venting adhesive patch 100. The self-venting patch 100 comprises a permanent (stronger bond) adhesive zone 210 meant to keep the patch in place and anchored to the bag. The characteristics of this adhesive allows it to stay adhered to the package under high pressure and temperatures during heating. A releasable (lesser bond) adhesive zone 220 that is intended to release from the package when under pressure due to heating. The characteristics of this adhesive allows it to lift away only when exposed to steam pressure in a microwave. The adhesives will partially re-adhere to package after cooking, providing a semi-sealed package and prevent leaks of liquids or sauces. Adhesives are designed to withstand exposure to cold, heat, oils, fats, and liquids for frozen food products and typical range of environments from packing, freezing and heating. The adhesives are food grade or suitable for indirect food contact. The two different adhesive zones can be defined by the size of the zones using the same adhesive, different types of adhesives in each zone, or the size and types of adhesives in each zone. The permanent (stronger bond) adhesive zone 210 may be same adhesive as the releasable (lesser bond) adhesive zone 220 however more adhesive may be utilized in a pattern providing lesser bond strength.

A non-adhesive zone 212 of the patch 100 covers a small opening 204 formed in a bag by a slit/perforations on rollstock film. The non-adhesive zone 212 can vary in shape and function for directing the flow of steam pressure and varying the vent release times. In the embodiment shown the non-adhesive zone 212 is provided in a generally triangular shape, having two sides adjacent the non-adhesive zone 212 and one side adjacent to the lesser bond zone 220. The holes or slits 204 can be formed in a variety of ways depending on the steam venting or cooking requirements. Openings in the bags can be formed in many shapes and configurations and include but not limited to slits, round holes, semicircular cuts, cross shaped cuts, v-shaped cuts, needle punches, laser perforations etc. Depending on the food product application and customer requirements a separation zone 230 between the releasable adhesive area (lesser bond) zone 220 and permanent adhesive zone (stronger bond) zone 210 can provide a stronger hermetic seal and/or allow pressure to build further before vent release. Varying the width of this threshold area is a simple way to control pressure levels inside the package by changing the time for vent release. Some situations may require a longer time period under pressure for desired cooking results.

The separation zone 230 separates during product heating and lift due to steam pressure. The separation zone 230 may utilize the same adhesive as permanent (stronger bond) adhesive zone with a lesser quantity as the permanent adhesive zone 210 in a narrow band that the steam has to break through to get to the releasable adhesive. The band can be ruptured due to the pressure of the venting to provide a hermetic seal prior to heating. Alternatively the separation zone may be sufficiently narrow to enable steam pressure to cause separation or rupture of the stronger bond adhesive in the narrow zone. The separation zone 230 may alternatively be defined by the absence of an adhesive, partial use of the adhesive, intermittent use of the adhesive, or use of a different type of adhesive or by the placement of another layer of patch material. As pressure increases the separation zone 230 will lift from the packaging material opening a portion 222. The separation zone 230 and the releasable adhesive area zone may comprise multiple or plurality of zone locations along or around the non-adhesive zone 212.

Specific design elements such as shape/measurements of the no-adhesive area 212, and the shape/measurements of the patch can be tailored for specific cooking needs, and is not limited to the example presented here. The patch may be formed in a number of shapes, for example circular, rectangular, triangular etc. The dimensions of the patch and the adhesive zones and non-adhesive zones may be variable depending on venting requirements. The patch may for example be 1″ in diameter although the dimensions may vary. However different shapes and zones can be utilized as would be understood by a person of skill in the art, the shape and orientation will depend on the type of bag, product being cooked, filling, venting and handling requirements. For example, the vent may be positioned towards the top of the package to reduce leakage of liquids when handled after cooking. The non-adhesive zone 212 can be absent of adhesive or substantially lack adhesive compared to the other adhesive zones of the patch.

FIG. 3 show a side view of the self-venting adhesive patch while venting is occurring. As the food within the packaging bag is heated by a microwave, steam pressure 300 vents through openings in the packaging material 104 applying pressure to the non-adhesive zone 212. As the non-adhesive zone 212 lifts, the separation zone 230 will also open and allow steam to move towards the releasable lesser bond adhesive zone 220 causing it to lift from the surface of the packaging material 104 enabling release of the steam 300. As the contents of the package cools and the steam pressure lowers, the separation zone 230 and/or the releasable adhesive zone 220 can partially reseal to the packaging material surface 104.

FIG. 4 shows a representation of a pillow packaging bag 400 having the self-venting adhesive patch 100. The patch 100 may be placed on portion 402, such as a fin seal 404 up the middle of the bag 400. The patch 100 can be positioned on a front panel or one or more of the two back panels (either side of the fin seal). The vent typically goes on one of the two back panels and the bag goes in the microwave face down such that the vent is positioned upright during cooking.

FIG. 5 shows a representation of a bottom gusset stand up pouch bag having the self-venting adhesive patch 100. The three-side bag having sealed sides portions 504 and bottom portion 506 to enable the bag 500 to stand up for filling through opening 510. The opening 510 of the bag is sealed once contents are placed in the bag 500. The vent 100 can be positioned at the top portion of the bag 500 to allow the steam to vent upwards.

As shown in FIG. 6, the patches such as self-venting patch 100 can be pre-applied on a rollstock product 600 (provided in roll form) with perforations made on the exterior of the rollstock product 600. The customer forms, fills and seals the package created from the rollstock product 600 in their packing facility or patches 100 a, 100 b can be applied inline on film web running on pre-made bag making machines or packer's form fill seal machines.

FIG. 7 shows a method 700 of manufacturing a flexible packaging bag having an adhesive patch. A rollstock material is received for forming the flexible packaging bag (702). The rollstock is made of laminated film structures for “microwave in bag” applications. The rollstock is cut or perforated to provide an opening (704) through the surface of the material. Each patch is aligned with the rollstock (706) and a patch is applied (708) to the material. The patch is applied by pressure sensitive adhesive. The rollstock is then utilized to form a package (710) with the patch being placed on the exterior of the package. The bag can then be filled (712) and then sealed (714). Alternatively, the self-venting adhesive patch 100 can be applied over a perforating/cut in the packaging bag after it is manufactured.

FIG. 8 shows a top view of an alternative embodiment of self-venting adhesive patch 800. The self-venting patch 800 comprises a permanent (stronger bond) adhesive zone 810 that keeps the patch 800 in place and anchored to the bag. A releasable (lesser bond) adhesive zone 820 is intended to release from the package when under pressure due to heating. A non-adhesive zone 812 is provided in a bulb shape or elliptical shape that covers the opening 204 formed in the bag by a slit/perforations on roll-stock film. A smaller portion of the non-adhesive zone 812 is directed towards the releasable (lesser bond) adhesive zone 820. A separation zone 830 can be provided between the permanent adhesive zone 810 and the lesser adhesive zone 820. The separation zone 830, and entry to the lesser adhesive zone 820, presents a proportionally lesser or shorter perimeter length than the perimeter of the permanent adhesive zone 810.

It would be appreciated by one of ordinary skill in the art that the system and components shown in FIGS. 1-8 may include components not shown in the drawings. For simplicity and clarity of the illustration, elements in the figures are not necessarily to scale, are only schematic and are non-limiting of the elements structures. It will be apparent to persons skilled in the art that a number of variations and modifications can be made without departing from the scope of the invention as defined in the claims. 

1. A self-venting adhesive patch made from a film material, the self-venting patch comprising: a permanent stronger bond adhesive zone applied to a surface of the film material; a releasable lesser bond adhesive zone adjacent to the permanent adhesive zone on the surface of the film material; and a non-adhesive zone within the permanent adhesive zone on the surface of the film for covering a vent formed in a microwavable packaging material covered by the self-venting adhesive patch, the non-adhesive zone directing steam pressure towards the releasable adhesive zone; wherein a package, formed from the microwavable packaging material, vents steam pressure to the self-venting adhesive generated during cooking of contents of the package, the steam pressure expands the non-adhesive zone and vents into the releasable adhesive zone, allowing steam to be vented from the vent, through the releasable lesser bond adhesive zone.
 2. The self-venting adhesive patch of claim 1 wherein the permanent adhesive is a stronger bond adhesive and the releasable adhesive zone is a lesser bond adhesive.
 3. The self-venting adhesive patch of claim 1 further comprising a separation zone between the permanent adhesive zone and the releasable adhesive zone.
 4. The self-venting adhesive patch of claim 3 wherein at least a portion of the separation zone may be formed by the permanent stronger bond adhesive zone.
 5. The self-venting adhesive patch of claim 1 wherein the non-adhesive zone is formed by application of a second film material over a portion of the permanent adhesive zone.
 6. The self-venting adhesive patch of claim 1 wherein the adhesives are food grade adhesives or adhesives suitable for indirect food contact.
 7. The self-venting adhesive patch of claim 1 wherein the vent within the packaging material the perforations are selected from a group comprising: slits, round holes, semicircular cuts, cross shaped cuts, v-shaped cuts, needle punches, and laser perforations.
 8. The self-venting adhesive patch of claim 1 wherein the adhesive patch is applied to packaging material roll-stock prior to forming a package from the flexible packaging material.
 9. The self-venting adhesive patch of claim 1 wherein the adhesive patch is applied to a formed package aligned with a perforation in a wall of the formed package.
 10. The self-venting adhesive patch of claim 1 wherein the releasable adhesive can partially re-seal to the microwavable packaging material when cooled after being heated.
 11. The self-venting adhesive patch of claim 1 wherein the shape of the non-adhesive zone provides proportionally larger perimeter length with the permanent adhesive zone than a perimeter length of the releasable adhesive zone.
 12. The self-venting adhesive patch of claim 1 wherein a separation zone is between the permanent adhesive zone and the releasable adhesive zone.
 13. The self-venting adhesive patch of claim 1 wherein the releasable lesser bond adhesive zone is formed by a plurality of sub-zones.
 14. The self-venting adhesive patch of claim 11 wherein the vent is formed by a semi-circular cut.
 15. The self-venting adhesive patch of claim 11 wherein the patch is circular shaped.
 16. The self-venting adhesive patch of claim 11 wherein the shape of the non-adhesive zone is triangular shaped.
 17. The self-venting adhesive patch of claim 11 wherein the shape of the non-adhesive zone is bulb shaped.
 18. A method of manufacturing a flexible package with an adhesive patch, the method comprising: receiving a rollstock material; perforating the rollstock material to form a vent opening; applying a self-venting adhesive patch of claim 1 to a side of the rollstock over the perforation in the rollstock material.
 19. A method of manufacturing an adhesive patch for application to a microwaveable package, the method comprising: applying a permanent adhesive to a film material in a permanent adhesive zone; applying a releasable adhesive to the film material adjacent to the permanent adhesive in a releasable adhesive zone; wherein a non-adhesive zone is formed within the permanent adhesive zone which allows the releasable adhesive zone to release from microwavable package when steam pressure is released from moisture in food contents within the microwavable package.
 20. The method of claim 19 wherein the adhesive patch is applied to roll-stock material for forming the flexible packaging material. 